1. Field of the Invention
The present invention concerns a power supply system for a long-stator drive for a magnetic levitation train.
Power supply systems for magnetic levitation trains are known that comprise a long-stator drive whose stator winding is subdivided into a plurality of controllable stator segments along a path of a magnetic levitation train. The stator segments can be connected through at least one segment switch along a section cable system running along the stator segments. Each section cable system provides at least one frequency transformer, with at least one frequency transformer arranged in at least one substation along the stator segments. The frequency transformer generates an appropriate supply voltage system for the stator segments. A power supply system with these features is known, for example, from German Patent 39 17 058 C1.
In the known embodiment, each section cable system is supplied by two frequency converters (double-supply). This arrangement reduces the current load on the section cable by one-half and creates redundancies suitable for emergency operation in the case of total failure of a frequency converter or the transformer substation. Under this configuration, the distance between transformer substations corresponds to the distance between consecutive trains.
In the substation itself, the high voltage of a power utility line is transformed into medium voltage and switched to the section cable system via a frequency converter with an output transformer, and finally to the stator segments. The frequency converter generates a system of variable frequencies and variable amplitudes.
Another power supply system is disclosed in German Patent 39 09 706 C2. This system also comprises a long-stator drive subdivided into a plurality of controllable stator segments along the path of a magnetic levitation train. The stator segments can be connected through at least one segment switch along the section cable system running along the stator segments. One or more frequency transformers generate a supply voltage system for the stator segments. In this power supply system, a supply voltage system is generated, via a single frequency transformer with an output transformer (this latter referred to as transformer in German Patent 39 09 706 C2). The supply voltage system is switched to the section cable system and ultimately to the stator segments.
Connecting two neighboring section cable systems together via a coupling switch is known from the paper "Long-stator Drive Power Supply" in the journal "etz," Vol. 108 (1987), 9, pp. 378 through 391, FIG. 5.
The paper "New Transrapid Drive Concept" in the journal "Eisenbahntechnische Rundschau ETR" (1989), Vol. 3, pp. 175 and 176, describes the bypassing of output transformers in the low-speed range (direct supply).
German Patent Application 41 30 779 A1 discloses the parallel connection of frequency transformers.